Generally, flow-control valves of the cartwheel type are known, as can be seen in the prior art references EP 1 099 455 and EP 0 336 307. Typically, they consist of a piece of silicone, or other elastomeric material, formed with a cartwheel that is fixed by the external ring to the valve casing and thus having freedom to move in only one direction when subjected to pressure. This mobility is typically due to the flexibility of the rods which connect the rim to the plug in the center of the valve. When assembled, with no pressure in the valve inlet, or when the pressure is applied in the opposite direction to the one intended, the valve is supported on the base or focus of the capsule, sealing the inlet and thereby preventing flow in the opposite direction. When pressure is applied in the intended flow direction, the valve moves, allowing the passage of flow between said rods. Therefore, it is configured as a unidirectional valve or anti-reflux valve.
There are some techniques in the market or types of valves that make anti-reflux function, such as, for example, the duckbill valve, umbrella type valve and said valves of the cartwheel type. However, these valves have some deficiencies of structural and functional nature that point to solutions not yet contemplated by the prior art, as commented below.
Duckbill Valve
This type of valve has a structure that favors the accumulation of waste in their inner corners, in addition to generating undesirable turbulence for certain applications, such as those in medicine. Add to that the fact that there is some difficulty to remove the valve inside the air. In addition, this valve has flow restrictions, since the liquid passage area is smaller than the area of the inlet connector. When used with air, it produces sound that can be disturbing depending on the application.
Umbrella Valve
The structure of this valve also favors the accumulation of waste in the corners, also generating undesirable turbulence for applications in medicine, particularly if the fluid is blood. They also have difficulty in extracting it from the inside air, as well as flow restriction, because the liquid passage area is smaller than the area of the inlet connector. If used with air, it produces uncomfortable noise depending on the application.
Cartwheel Valves
This type of valve, as disclosed in prior art documents EP 1 099 455 and EP 0 336 307, because the central plug plan format, also generates accumulation of waste in the inner corners, in addition to the already mentioned undesirable turbulence, especially when the fluid is blood. Furthermore, due to the central plug plan format, if subjected to high suction pressures in the inlet, it can deform and thus allow the passage of flow. Additionally, if it is used in long-term applications, said central plug plan format can suffer deformations that may lead to fluid leaks. Finally, the central plug plan format of the valve limits its work for only one direction of flow, not being possible its application as a three or more-way valves.
Another problem observed in the low control devices of the current state of the art, mainly when used in medicine, such as in hemodynamic and infusion substances to patients where it is necessary to control one or more fluid flows by three or more paths, relates to arrangements used. In general, it relates to flow driver devices consisting of taps, records and manifolds, which require the gauntlets handling to obtain the direction of flow to the desired outlet. Obviously, this handling is not suitable and can even generate problems for due process that the patient is undergoing.
It is, however, an objective of the present invention minimize and even solve the aforementioned problems, through the provision of a flow-control valve of the cartwheel type, with proper constructive characteristics and made of silicone, rubber, flexible PVC or other elastomeric material that meets the necessary flexibility specifications and resistance to valve operation, enabling better adjustments and reliability for characteristics such as opening pressure, maximum flow, flow resistance, biocompatibility, durability, etc.
It is another objective of the present invention to provide a unidirectional flow-control valve of the cartwheel type, with peculiar constructive characteristics so that it can alternatively and selectively as design option, work in both sides of the valve, as a sealing or for passage of fluid flow.
Among the many improvements and advantages that the constructive characteristics of the flow-control valve of the cartwheel type, object of the present invention, can present in relation to those of prior art, stand out:                Better sealing between the plug and the base of the capsule, obtained by the arch-shaped fitting of the plug with the base of the capsule. Thus, the higher the pressure the better the sealing, with no reflux even when the valve deforms with pressure;        Due to the arch format in both sides of the valve, depending on the inner format of the base of the capsule, when in a system or arrangement of three ways or more, it is possible to work with the valve plug sealing or giving passage to the fluid flow, as alternative of chosen inlets and outlets.        
Yet another object of the present invention is to provide arrangements with flow-control valves of the cartwheel type, replacing the current flow drivers, so that the operation is fully automatic and safe. Said arrangements in cartwheel-type valves according to the present invention have the following advantages over the current flow drivers:                Fully automatic and safe operation, without the need to turn any gauntlet or device, with no risk of error in the required flow direction;        Low cost, because it is not necessary to use several maneuvering devices simultaneously;        Reduced size in relation to prior art devices.        